Water is the most underrated of the falling costs. Desalination via reverse osmosis has dropped substantially in cost over the past several decades and continues to fall. Atmospheric water generation — pulling potable water from humid air — is reaching prices viable for drought-prone communities. Membrane and treatment technology is making greywater reuse, and even toilet-to-tap reuse, practical at municipal scale.
What makes water different is that scarcity has always been geographic rather than technological. The falling costs change the geography. Communities that could not have had reliable water at any price are entering range. The ownership question is whether the new water flows through public utilities accountable to communities, or through privatized concessions sold to municipalities under duress.